Escape staircase and method for allowing occupants of a building to escape safely during an emergency

ABSTRACT

A multistory emergency stairwell structure for escape and rescue in different emergency situations adapted for building proximate to a pre-existing multistory building, and being built as a separate construction from the pre-existing building for facilitating passage of occupants between the pre-existing building and the stairwell structure by means of a passageway that is attached at one end only to either the pre-existing building or to the stairwell structure and is free to move at its opposite end.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of Israel Patent Application No. 222887 filed on Nov. 5, 2012 hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

This invention relates to external emergency multi-story staircases for allowing escape from a building in different emergency situations.

BACKGROUND OF THE INVENTION

Different types of emergency staircases are known that allow for the escape of residents from a building in the case of fire. Emergency staircases may be located either inside an existing building or external thereto such as external stairs that are attached to the building.

From experience, there frequently arises the need to add an emergency staircase outside existing buildings in order to improve the safety level. Such staircases are implemented by being directly connected to the building.

In the event that occupants need to escape via the staircase during an earthquake, known emergency staircases provide no safety if attached to buildings that do not withstand earthquakes The extent to which such staircases are able to withstand earthquakes is the same as the building to which they are attached. In other words, the staircase will not meet seismic safety standards if they are attached to a building that does not itself meet these standards. The collapse of the building, or a part of the building next to such emergency staircases, will give rise to the emergency staircase collapsing in an earthquake. Existing emergency staircases will not give rise to a higher safety level than that of the complete building itself.

Staircases as well as enclosed staircases of various types are also known within a building or connected thereto and which constitute the weak link of the building owing to the difference in dynamic properties of the staircases as compared with the rest of the building. Based on experience in many cases, the staircases are the first thing to be affected in an earthquake and thus do not provide a safe escape for the building's occupants. After the staircase has been hit by an earthquake or an explosion, the occupants are liable to remain trapped in the building and to suffer from explosion waves of the earthquake, additional explosions, or fires.

Existing emergency staircases are not protected to the same level as a shelter or protected space and provide no answer to safety in times of war in accordance with the relevant standards relating thereto as well as to systems intended for use therewith.

In general, apart from fire escapes, use of emergency staircases is not known for other emergency situations such as earthquakes and war on the home front, for use with buildings that do not meet the relevant seismic standards or with buildings whose enclosures are not protected. This need arises due to historical defaults in the design of buildings against earthquakes and due to the paucity of shelter solutions.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the invention provides a multi-story emergency stairwell structure for different emergency situations adapted for construction proximate a pre-existing multi-story building and which is constructed as a separate building from the pre-existing building and is not constructively coupled thereto and which allows for passage of occupants between the pre-existing building and the stairwell structure by means of a passage that is attached at one end only and is free to move at its opposite end.

In accordance with a second aspect of the invention, there is provided a method for providing safety to occupants of pre-existing multi-story buildings in an emergency, wherein the method includes:

(a) erecting at the side of a pre-existing building an escape stairwell structure;

(b) establishing between the pre-existing building and the escape stairwell structure a passage for enabling occupants to exit the pre-existing building even during an earthquake, said passage being attached at one end only and being free to move at its opposite end.

DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing the entry level of a stairwell structure and means for allowing the escape of occupants from the building;

FIG. 2 is a schematic diagram showing a typical stairwell structure and means for allowing the escape of occupants from the building; and

FIG. 3 is a sectional view through line A-A of the stairwell structure and the pre-existing building.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The disadvantages of known emergency staircases are overcome by the proposed invention. This is achieved by use of the following elements:

To a pre-existing building 1 that does not meet the seismic safety standards and/or a building where it is required to increase the safety level and/or a building whose enclosures are not protected, there is added an external stairwell structure 2 which is a separate construction from the pre-existing building 1. The stairwell structure 2 meets the seismic standard in accordance with the Israeli Standard 413 and corresponding US standards, withstands fire, includes a system for extinguishing fires in accordance with the relevant standards, is protected against shrapnel and surplus pressure as necessary and meets the Home Front Command's standards. The stairwell structure 2 also withstands forces caused by the collapse of the pre-existing building 1. Likewise, in accordance with the requirements of the relevant standards, it is desirable that the stairwell structure 2 be enclosed and include a filter system for protection against nuclear, biological, and chemical contamination. To the same extent, the stairwell structure 2 includes auxiliary systems such as electrical power supplies, toilets, drinking water and the like. These auxiliary systems are known per se and are installed inside the stairwell structure 2 in a manner that is also known per se, albeit for use in other buildings, and are therefore not described herein.

As shown in FIGS. 1, 2, and 3, the pre-existing building 1 is located opposite to stairs 4 of the stairwell structure 2 and provides new openings 6 having doors for the escape of occupants from the pre-existing building 1 to the stairwell structure 2. Preferably, there are an equal number of stories in the stairwell structure 2 as there are in the pre-existing building 1 and each story of the stairwell structure 2 is at the same height as the corresponding story of the pre-existing building 1.

The stairwell structure 2 may be implemented from constructions of different types, for example, walls 5 of the stairwell may be formed from Class 60 reinforced concrete having a thickness of 20-30 cm. The passageways of the stairwell structure 2, platforms and the high bottom beams as shown in FIG. 3 may be formed of Class 40 reinforced concrete having a thickness of 16-18 cm. The upper plate of the stairwell structure 2 as shown in FIG. 3 may be made of Class 60 reinforced concrete having a thickness of 25-35 cm. External elements of the stairwell structure 2 such as the walls 5 in addition to their withstanding earthquakes, must be able to withstand aftershocks and shrapnel, as well as being able to withstand forces caused by the collapse of the pre-existing building 1. The stairwell structure 2 includes a foundation 7, for example, a foundation plate formed of Class 40 reinforced concrete having a thickness of 30 cm with high bottom beams of reinforced concrete having a height of 100 cm.

In order to reduce seismic forces of the stairwell structure 2, seismic isolation 15 of different types may be disposed between the foundation 7 and a base of the stairwell structure 2, for example, rubber-steel supports. In order to reinforce the stairwell structure 2 against explosions, an additional internal shield 16 may be provided such as by means of steel plates having a thickness of 6-12 mm formed of Class St 52 steel. The shield 16 facilitates connection between the inner side of the walls 5 and an upper roof plate.

The stairwell structure 2 includes doors 17 capable of withstanding surface pressure and shrapnel and windows 18 shielded against surface pressure and shrapnel. The doors 17 and the windows 18 are off the shelf items that are installed in accordance with the requirements of the Home Front Command. Several systems are also installed in the stairwell structure 2 for extinguishing fires, ventilation, air filtering, electricity, emergency lighting, water containers, communication and other systems as required by the Home Front Command and which are not marked in FIGS. 1, 2 and 3.

Between the pre-existing building 1 and the stairwell structure 2, there is disposed a movable passageway 3 which allows for passage of occupants to the stairwell structure 2 in times of emergency. Within the context of the description and appended claims, the term “movable” when applied to the passageway 3 denotes that the passageway 3 is fixed at one end to either the pre-existing building 1 or to the stairwell structure 2 but not to both. Typically, it is attached at one end to the pre-existing building 1, its opposite being capable of sliding movement relating to the stairwell structure 2. By such means, movement of the pre-existing building 1 during an earthquake allows the opposite end of the passageway 3 to move relative to the pre-existing building 1 without subjecting force to the stairwell structure 2. The movable passageway 3 may be a steel plate for example, formed of Class St 37 steel having a thickness of 12-16 mm. The steel plate is connected at one end to the outside wall of the pre-existing building 1 by means of a pivot joint 3A, and at the opposite end rests freely on the stairwell structure 2. The pivot joint 3A of the plate at one end and the free movement at the opposite end allow the movable passageway 3 to withstand differential movement between the pre-existing building 1 and the stairwell structure 2.

Stairs 4 of the stairwell structure 2 are designed in accordance with established architectural guidelines for emergency stairwells. On the entrance level of the stairwell structure 2, there is formed a protected passageway 2A that allows for escape via the lower exit or primary exit 8 and to permit the fleeing occupants to move far away from the pre-existing building 1 in time of emergency (for example, to prevent risk owing to the collapse of the pre-existing building 1, collapse of parts of the pre-existing building 1, fire, and so on). Normally open explosion wave doors 17 allow for passage of escaping occupants and close only if the occupants need to remain inside the stairwell structure 2 when used as a protected space in emergencies such as war on the Home Front.

The stairwell structure 2 also has an upper exit on a roof 9 (subsidiary exit) in order to increase the likelihood of survival of occupants inside the stairwell structure 2 under severe emergency conditions. In order to climb to the roof 9, there is provided an internal ladder 12 as shown in FIG. 3, which allows an occupant to climb to the roof 9 also by another stair unit in an addition to the stairs 4 to the roof 9. A rescue team can rescue the occupants from the roof 9 of the stairwell structure 2 by a ladder, crane, helicopter, ropes, and the like. They can also be rescued by an external ladder 13 having a protected cage extending from the roof 9 to the ground. The external vertical ladder 13 is combined with a platform 14 for safety. Emergency equipment is provided on the roof 9 as required for using ladders, for example, ropes, harnesses, falling brakes, and so on. These additional exits are intended to provide safety and means for escaping when the ground level exits on each story of the pre-existing building 1 are blocked owing to an emergency event or in the event of fire on the lower story.

Safety railings 10 are disposed on opposing sides of the passageway 3 in the space between the pre-existing building 1 and the stairwell structure 2. On the roof 9 above the spacing between the pre-existing building 1 and the stairwell structure 2, there is disposed a movable roof shield 11, made of steel plates, for example, by means of Class St 52 steel plates having a thickness between 24-32 mm. Within the context of the description and appended claims, the term “movable” when applied to the roof shield 11 denotes that the roof shield 11 is fixed at one end to either the pre-existing building 1 or to the stairwell structure 2 but not to both. By such means, movement of the pre-existing building 1 during an earthquake allows the opposite end of the roof shield 11 to move relative to the pre-existing building 1 without subjecting force to the stairwell structure 2. The roof shield 11 is installed at angles of about 45 degrees, one end being articulated to the high concrete beam on the roof 9 of the stairwell structure 2, by means of a pivot joint 11A, and at its opposite end the roof shield 11 rests freely on the external wall of the pre-existing building 1.

The stairwell structure 2 in addition to what is stated above, must also withstand loads arising from the collapse of the pre-existing building 1. Consequently, when used for protection against earthquakes, the stairwell structure 2 must be built in accordance with seismic standards and shielded as required so as to be sufficiently strong and remain standing. The stairwell structure 2 was analyzed using computer structural simulation software under different emergency conditions and was found to provide a secure passageway 3 from the pre-existing building 1 to the stairwell structure 2, increasing the security level of the stairwell structure 2 above that of the pre-existing building 1 and ensuring that occupants can escape the pre-existing building 1 in time of need. In FIGS. 1, 2 and 3, there is shown schematically the escape of occupants from the pre-existing building 1 through the primary exit 8. Arrows are marked in the schematic diagrams, such that the direction of the arrow shows the direction in which the occupants escape. This is important for efficient operation of the stairwell structure 2 during an emergency since the direction of the arrows in the drawings constitutes the direction of movement of the occupants in time of emergency. Movement of the occupants on the stairs 4 in accordance with FIGS. 1, 2 and 3 represents the optimal route for escape of the occupants including the optimal meeting between the streams of moving occupants, movement within the stairwell structure 2 in the same direction on all stories (for example, according to FIGS. 1 and 2 movement of the occupants is effected in a counter-clockwise direction only), distancing the occupants from the risk-laden pre-existing building 1 after their escape.

The stairwell structure 2 need not be used only in case of emergency or when an emergency occurs. Thus, owing to the composition and properties of the stairwell structure 2 described above, it may be used for rescuing occupants after an emergency event by means of teams of rescue units from the Home Front or fire extinguishing team as well as others. This is rendered possible owing to the high survivability of the stairwell structure 2 in different emergency situations, which cannot be achieved using current emergency staircases.

Examples for Efficient Use of the Proposed Stairwell Structure

1. Efficient erection of the stairwell structure 2:

a. the stairwell structure 2 may be erected quickly from reinforced concrete using space pre-cast blocks, for example, factory-made single-story elements with connections that are suited to the forces applied on the stairwell structure 2.

b. in the pre-cast stairwell structure 2 method described in paragraph ‘a’, joints may be used having the following components: steel metal plates anchored in corresponding pre-cast concrete units, assembling alongside metal plate connections, and fastening using screws. For example, thickness of the steel plates may be 16-20 mm, of Class St 52 steel. The diameter of the screws is 24-32 mm having a hardness level between 8.8-10.9. In the steel plate anchored to the concrete there are provided holes complementary to those for the screws in the side connection plates. This connection allows energy of oscillations to be damped.

c. use of the stairwell structure 2 is multi-functional and may be used in accordance with a number of emergency conditions, for example: earthquakes, war on the Home Front, and fire.

d. use of the stairwell structure 2 having more than ten stories may provide an answer for increasing the safety of vast numbers of pre-existing buildings 1 requiring it.

Operational Efficiency

a. escape during an earthquake or fire and congregating within protected spaces at the time of war on the Home Front conforms to the emergency guidelines of many countries including Israel and the USA.

b. use of a differential alarm system or warning system that deals with each emergency situation separately.

c. occupants undergo training and escape exercises in accordance with vocal commands provided by the alarm system or without an alarm system, while listening to instructions on the radio or self-detection as to when an emergency situation commences. Signs are installed in the pre-existing building 1 specifying the required action for each relevant emergency situation.

d. the invention affords safe escape to the occupants of pre-existing buildings 1 that suffer from the following main defects:

i. does not meet the seismic safety standards;

ii. does not have protected spaces;

iii. does not have an emergency fire staircase;

These defects are the main ones, but there are also other factors that require that the safety of the occupants be augmented.

Existence of these defects in pre-existing buildings 1 is established in accordance with the relevant current regulations and standards in each field.

Signs in the pre-existing building 1 and in the stairwell structure 2 can indicate recommended course of action for the occupants in every situation and Instructions and exercises for the occupants regarding use of the alarm system and recommended course of action.

The warning system may be configured for receiving seismic waves of Type P or S and for transmitting a warning in real time of receipt of P waves (Type P waves that do not damage the buildings precede the earthquake which arrives with S waves that subject the buildings to risk) and as a result convey a warning before commencement of an earthquake and significantly improves the chances for occupants to escape.

Preferably, the warning system is optimized according to the different types of emergency condition under which the stairwell structure 2 is intended for use and also according to the size of the region encompassed by the alarm. Thus, the warning system provides different directions for an earthquake than it does for a fire or an attack on the Home Front. In a fire, the primary concern is to get the occupants as far away as possible from the pre-existing building 1 on fire: the farther the better. To this end, the stairwell structure 2 merely serves as a safe passage—‘passage’ being the operative word in that it serves to allow the occupants to exit the pre-existing building 1 safely and, having done so, to exit also the stairwell structure 2 and move even farther from the burning pre-existing building 1. An alarm system that is adapted for fires preferably includes smoke detectors and other instrumentation within the pre-existing building 1 and transmits in real time a fire alarm that is implemented by means of an alarm, vocal instructions and additional means for allowing occupants to escape outside using the emergency stairwell structure 2. But in an earthquake, very different safety directions are required since the stairwell structure 2 provides safe harbor from the earthquake provided that the fleeing occupants remain secluded in the stairwell structure 2. In this case, the warning system is preferably adapted to issue directions under an earthquake condition for receiving seismic waves of Type P or S and transmitting a warning in real time of receipt of P waves and as a result convey a warning before commencement of an earthquake and thereby significantly improve the chances for occupants to escape.

The warning system is adapted to provide directions to occupants in the pre-existing building 1 how to react according to a detected emergency situation. To this end, different sensors are used to provide an indication of the threat or emergency situation and the alarm system is responsive thereto for directing the occupants how to respond.

As noted above, the size of the region encompassed by the alarm may also dictate different types of instructions or directions that are most are most appropriate for behavior on land, in a public building, a municipality, a defined district, and private premises. For example, a simple standalone system for a private building may direct people to exit the stairwell structure 2 or to remain inside and close the doors 17 to the passageways 3. Conversely, a municipal or district alarm may alert civilians in an attack on the Home Front to congregate at a specified central location that may have more sophisticated or comprehensive protection than can be reasonably be provided in a private dwelling.

The appended claims may recite features that are not described in the foregoing description. To this end, the claims are to be regarded as part of the description and are intended to provide support for all such features.

LEGENDS

-   1 The external wall of the pre-existing building -   2 External stairwell structure being a separate construction that     meets seismic standards and may be designed to withstand additional     emergency situations -   2A Part of the stairwell structure 2 that provides a protected     passageway for escape via the lower exit and for distancing the     occupants from a pre-existing building -   3 Passageway between the pre-existing building and the stairwell     structure. -   3A Pivot joint of the passageway. -   4 Platform of the stairs, Emergency stairs meeting the requisite     standards. -   5 Concrete walls of the stairwell structure. -   6 New opening and door in the pre-existing building for exit to the     stairwell structure. -   7 Foundation of the stairwell structure -   8 Lower exit from the stairwell structure (primary exit) -   9 Upper exit from the stairwell structure (secondary exit) -   10 Safety rail on both sides of the passageway in the space between     the pre-existing building and the stairwell structure -   11 Roof shield made of steel plate over the space between the     pre-existing building and the stairwell structure -   11A Pivot joint of the roof shield -   12 Internal ladder leading up to the roof -   13 External ladder from the roof of the stairwell structure to the     ground with at least one horizontal platform -   14 Horizontal platform of the external ladder -   15 Seismic isolation (if required) -   16 Internal shield in the stairwell structure formed of steel plates     (if required) -   17 Door able to withstand explosion wave -   18 Window shielded against explosion wave -   Direction of escape of occupants from the pre-existing building     through the primary exit (the direction of the arrow is the     direction of escape) 

What is claimed is:
 1. An emergency staircase for escape and rescue from a pre-existing building comprising: a stairwell structure proximate the pre-existing building and having a plurality of stairs disposed therein; and at least one passageway structure having an end, the end pivotally coupled to one of the pre-existing building and the stairwell structure.
 2. The emergency staircase according to claim 1, wherein the stairwell structure is adapted for a seismic standard greater than a seismic standard of the pre-existing building.
 3. The emergency staircase according to claim 1, wherein the stairwell structure has a plurality of stories corresponding to a plurality of stories of the pre-existing building, each of the plurality of stories of the stairwell structure is adapted to assemble occupants separately from the pre-existing building.
 4. The emergency staircase according to claim 1, wherein the stairwell structure is constructed from materials that withstand fire.
 5. The emergency staircase according to claim 1, wherein the stairwell structure includes a warning system adapted to provide a plurality of directions to occupants in the pre-existing building and the stairwell structure.
 6. The emergency staircase according to claim 5, wherein the warning system is adapted to receive Type P seismic waves and Type S seismic waves and transmit a warning in real time upon receipt of at least the Type P seismic waves.
 7. The emergency staircase according to claim 5, wherein the warning system is adapted to transmit in real time a warning from an authorized agency.
 8. The emergency staircase according to claim 1, wherein the passageway structure is a plate.
 9. The emergency staircase according to claim 1, wherein the stairwell structure is formed with at least one of reinforced concrete and a plurality of pre-cast building elements.
 10. The emergency staircase according to claim 1, wherein the stairwell structure includes a plurality of walls and a roof enclosing the stairs, the roof having an upper exit to facilitate rescuing.
 11. The emergency staircase according to claim 10, wherein the stairwell structure further includes at least one of an internal ladder extending from the roof towards a base of the stairwell structure and an external ladder extending from the roof to the ground.
 12. The emergency staircase according to claim 10, wherein the stairwell structure includes an internal shield and a roof shield, the internal shield configured to facilitate connection between the inner side of the walls and an upper roof plate of the roof, and the roof shield coupled to one of the stairwell structure and the pre-existing building.
 13. The emergency staircase according to claim 1, further comprising a seismic isolation disposed intermediate a foundation of the stairwell structure and a base of the stairwell structure for minimizing seismic forces applied to the stairwell structure.
 14. The emergency staircase according to claim 1, further comprising a door disposed in the stairwell structure adjacent the at least one passageway structure, wherein the door is a normally open explosion wave door.
 15. The emergency staircase according to claim 1, further comprising a protected passageway structure formed in the stairwell structure extending towards a primary exit of the stairwell structure.
 16. An emergency staircase for escape and rescue from a pre-existing building comprising: a stairwell structure proximate the pre-existing building and having a plurality of stairs disposed therein, the stairwell structure including a plurality of walls and a roof enclosing the plurality of stairs, the roof having an upper exit to facilitate rescuing; and at least one passageway structure having a pair of opposing ends, one of the pair of opposing ends is pivotally coupled to one of the pre-existing building and the stairwell structure and another of the pair of opposing ends is movable relative to an other of the one of the pre-existing building and the stairwell structure.
 17. The emergency staircase according to claim 16, wherein the stairwell structure is adapted for a seismic standard greater than a seismic standard of the pre-existing building, the stairwell structure having a plurality of stories corresponding to a plurality of stories of the pre-existing building, and each of the plurality of stories of the stairwell structure is adapted to assemble occupants separately from the pre-existing building.
 18. A method for providing safety to occupants of a pre-existing building in an emergency, comprising the steps of: erecting a stairwell structure in proximity of a pre-existing building, the stairwell structure having a seismic standard greater than a seismic standard of the pre-existing building, the stairwell structure including a plurality of walls and a roof enclosing the plurality of stairs; establishing at least one passageway structure between the pre-existing building and the stairwell structure, the at least one passageway structure having an end coupled to one of the pre-existing building and the stairwell structure.
 19. The method according to claim 18, further comprising the steps of: forming at least one opening in the pre-existing building opposite the at least one passageway structure of the stairwell structure; providing a door adjacent the at least one passageway structure of the stairwell structure; and affixing pivot joints to the at least one passageway structure to provide movement of the at least one passageway structure between the pre-existing building and the stairwell structure.
 20. The method according to claim 18, further comprising providing a warning system that is adapted to receive information and provide warnings dependent on the information received. 